This invention generally relates to the art of electrical connectors and, particularly, to a retention system for a surface mounted electrical connector on a printed circuit board.
There are a wide variety of electrical connectors which are designed for mounting on a printed circuit board. The connectors include dielectric housings which mount a plurality of conductive terminals. Often, a metal shield substantially surrounds the housing to protect the interconnected circuits from radio frequency (RF) and/or electromagnetic (EMI) interference. In some connectors, the terminals have tail portions and the shield has leg portions, with the tail portions and leg portions extending downwardly from the housing for insertion into appropriate holes in the printed circuit board. In other connectors, often called xe2x80x9csurface mountxe2x80x9d connectors, the tail portions of the terminals are bent for surface engaging circuit traces on the surface of the printed circuit board.
With surface mounted electrical connectors of the character described above, typically there are two different approaches for electrically connecting the shields of the connectors to appropriate ground circuit traces on the printed circuit board. One approach simply employs board-mounting tabs integral with the shields and bent into configurations for surface connection, as by soldering, to the ground circuit traces on the printed circuit board. With such integral mounting tabs, considerable problems are encountered in maintaining the mounting tabs of the shield coplanar with the surface engaging tail portions of the terminals. Without coplanarity, defective connections may result when the mounting tabs and tail portions are soldered to the circuit traces on the circuit board.
Another approach is to use separate conductive metal retaining clips which are mounted on the dielectric housing of the connector, with the retaining clips including board mounting tabs. However, the separate retaining clips must be maintained in mechanical and electrical engagement with the shield of the connector, and problems often are encountered in guaranteeing good electrical continuity between the shield and the retaining clips.
The present invention is directed to solving these problems in a retention system which uses surface mounted retaining clips with a unique system for electrically coupling the retaining clips to the connector shields.
An object, therefore, of the invention is to provide a new and improved retention system for a surface mounted electrical connector on a printed circuit board.
In the exemplary embodiment of the invention, a dielectric connector housing is adapted for mounting on a surface of the printed circuit board. A plurality of terminals are mounted on the housing for engaging appropriate circuit traces on the printed circuit board. At least one retaining clip is mounted on the housing and includes a board-mounting tab for solder connection to an appropriate ground trace on the surface of the printed circuit board. The mounting tab has an opening. A conductive shield is disposed about portions of the housing and includes a projection extending into the opening in the board-mounting tab of the retaining clip. Therefore, during solder connection of the retaining clip to the circuit board, solder material engages the projection of the shield through the opening in the mounting tab to thereby mechanically and electrically secure both the retaining clip and the shield to the printed circuit board.
As disclosed herein, the board mounting tab of the retaining clip extends generally parallel to the surface of the printed circuit board for surface-engagement therewith. The shield includes a wall extending generally perpendicular to the surface of the printed circuit board. The projection on the shield is located at a bottom edge of the wall. Preferably, at least a pair of the retaining clips are mounted on the housing at opposite sides thereof.
Another feature of the invention is to provide a redundant coupling path between the conductive shield and the retaining clip. In particular, the retaining clip includes a body mounted to the connector housing. The board mounting tab projects from the body. In addition, an engagement flange also projects from the body for engaging the shield to provide a secondary or redundant conductive path from the ground trace on the printed circuit board, through the retaining clip, to the shield. The housing also includes a locking flange engageable by the engagement flange of the retaining clip, whereby the engagement flange performs a dual function of locking the retaining clip to the housing.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.